4,574 research outputs found

    Polaritonic characteristics of insulator and superfluid phases in a coupled-cavity array

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    Recent studies of quantum phase transitions in coupled atom-cavity arrays have focused on the similarities between such systems and the Bose-Hubbard model. However, the bipartite nature of the atom-cavity systems that make up the array introduces some differences. In order to examine the unique features of the coupled-cavity system, the behavior of a simple two-site model is studied over a wide range of parameters. Four regions are identified, in which the ground state of the system may be classified as either a polaritonic insulator, a photonic superfluid, an atomic insulator, or a polaritonic superfluid.Comment: 7 pages, 9 figures, 1 table, REVTeX 4; published versio

    Foot and Mouth Epidemic Reduces Cases of Human Cryptosporidiosis in Scotland.

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    In Scotland, rates of cryptosporidiosis infection in humans peak during the spring, a peak that is coincident with the peak in rates of infection in farm animals (during lambing and calving time). Here we show that, during the outbreak of foot and mouth disease (FMD) in 2001, there was a significant reduction in human cases of cryptosporidiosis infection in southern Scotland, where FMD was present, whereas, in the rest of Scotland, there was a reduction in cases that was not significant. We associate the reduction in human cases of cryptosporidiosis infection with the reduction in the number of young farm animals, together with restrictions on movement of both farm animals and humans, during the outbreak of FMD in 2001. We further show that, during 2002, there was recovery in the rate of cryptosporidiosis infection in humans throughout Scotland, particularly in the FMD-infected area, but that rates of infection remained lower, though not significantly, than pre-2001 levels

    Concentration and purification of entanglement for qubit systems with ancillary cavity fields

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    We propose schemes for entanglement concentration and purification for qubit systems encoded in flying atomic pairs. We use a cavity-quantum electrodynamics setting as the paradigmatic scenario within which our proposals can be implemented. Maximally entangled pure states of qubits can be produced as a result of our protocols. In particular, the concentration protocol yields Bell states with the largest achievable theoretical probability while the purification scheme produces arbitrarily pure Bell states. The requirements for the implementation of these protocols are modest, within the state of the art, and we address all necessary steps in two specific set-ups based on experimentally mature microwave technology.Comment: 10 pages, 6 figure

    Dynamics in a coupled-cavity array

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    The dynamics of a system composed of two coupled optical cavities, each containing a single two-level atom, is studied over a wide range of detuning and coupling values. A description of the field in terms of delocalized modes reveals that the detuning between the atoms and these modes is controlled by the coupling between the cavities; this detuning in turn governs the nature of the dynamics. If the atoms are highly detuned from both delocalized field modes, the dynamics becomes dispersive and an excitation may be transferred from the first atom to the second without populating the field. In the case of resonance between the atoms and one of the delocalized modes, state transfer between the atoms requires intermediate excitation of the field. Thus the interaction between the two atoms can be controlled by adjusting the coupling between the cavities.Comment: 11 pages, 3 figure

    Elastic cavitation, tube hollowing, and differential growth in plants and biological tissues

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    Elastic cavitation is a well-known physical process by which elastic materials under stress can open cavities. Usually, cavitation is induced by applied loads on the elastic body. However, growing materials may generate stresses in the absence of applied loads and could induce cavity opening. Here, we demonstrate the possibility of spontaneous growth-induced cavitation in elastic materials and consider the implications of this phenomenon to biological tissues and in particular to the problem of schizogenous aerenchyma formation

    First Results from the CHARA Array. II. A Description of the Instrument

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    The CHARA Array is a six 1-m telescope optical/IR interferometric array located on Mount Wilson California, designed and built by the Center for High Angular Resolution Astronomy of Georgia State University. In this paper we describe the main elements of the Array hardware and software control systems as well as the data reduction methods currently being used. Our plans for upgrades in the near future are also described

    Source attribution, prevalence and enumeration of Campylobacter spp. from retail liver

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    Funding Information: We thank Food Standards Agency, Scotland for funding this work.Peer reviewedPreprin

    Seismicity and crustal structure of the southern main Ethiopian rift: new evidence from Lake Abaya

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    The Main Ethiopian Rift (MER) has developed during the 18 Ma-Recent separation of the Nubian and Somalian plates. Extension in its central and northern sectors is associated with seismic activity and active magma intrusion, primarily within the rift, where shallow (urn:x-wiley:15252027:media:ggge22586:ggge22586-math-00015 km) seismicity along magmatic centers is commonly caused by fluid flow through open fractures in hydrothermal systems. However, the extent to which similar magmatic rifting persists into the southern MER is unknown. Using data from a temporary network of five seismograph stations, we analyze patterns of seismicity and crustal structure in the Abaya region of the southern MER. Magnitudes range from 0.9 to 4.0; earthquake depths are 0–30 km. urn:x-wiley:15252027:media:ggge22586:ggge22586-math-0002 ratios of urn:x-wiley:15252027:media:ggge22586:ggge22586-math-00031.69, estimated from Wadati diagram analysis, corroborate bulk-crustal urn:x-wiley:15252027:media:ggge22586:ggge22586-math-0004 ratios determined via teleseismic P-to-S receiver function H-urn:x-wiley:15252027:media:ggge22586:ggge22586-math-0005 stacking and reveal a relative lack of mafic intrusion compared to the MER rift sectors to the north. There is a clear association of seismicity with the western border fault system of the MER everywhere in our study area, but earthquake depths are shallow near Duguna volcano, implying a shallowed geothermal gradient associated with rift valley silicic magmatism. This part of the MER is thus interpreted best as a young magmatic system that locally impacts the geothermal gradient but that has not yet significantly modified continental crustal composition via rift-axial magmatic rifting

    Squirrelpox in a red squirrel in Fife

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    SQUIRRELPOX has been identified as a key factor in red squirrel (Sciurus vulgaris) decline in the UK.1 Grey squirrels (Sciurus carolinensis) are thought to act as reservoir hosts for squirrelpox virus (SQPV), the causative agent of squirrelpox, with a reported asymptomatic seroprevalence of 61 per cent.2SQPV is implicated in the complete replacement of red squirrels by grey squirrels throughout mainland England and Wales,1 and poses a major threat to Scottish red squirrel populations since being first detected in 2007.3 To combat this threat, an mortality surveillance programme has been established at the Royal (Dick) School of Veterinary Studies, University of Edinburgh, using opportunistic sampling of red squirrel carcases. This has been ongoing for several years, including a summary publication covering 262 cases submitted from 2005 to 2009.4As part of this monitoring programme, an adult female red squirrel carcase was submitted by a member of the public, after having been found in Townhall Wood (NT110894), on the outskirts of Dunfermline, Fife, in March 2024. Postmortem examination identified multiple lesions typically associated with squirrelpox, including ulcerative and exudative dermatitis of the periocular and perioral skin (Fig 1). Histopathology of the affected skin identified extensive ulceration alongside remnant areas of epithelium with marked ballooning degeneration and eosinophilic intracytoplasmic inclusion bodies. Transmission electron microscopy of the affected tissue also identified numerous pox virions within the affected tissue, which through their size, shape and available surface morphology (Fig 2), were consistent with those of SQPV. In Britain there have been no additional identified diseases in red squirrels that present with periocular or perioral, ulcerative to exudative dermatitis due to a poxvirus,5indicating this case is highly likely due to SQPV.This finding represents the first identification of squirrelpox north of the central belt and is consistent with the predictions of previous modelling, which identified a high risk of northern SQPV spread from 2023 onwards.6 This modelling also suggests a rapid increase and spread of squirrelpox into more northerly and naive red squirrel populations is likely following establishment north of the central belt in central Scotland.6This case and modelling supports an increased requirement for targeted investigations, ongoing monitoring and grey squirrel interventions both around Dunfermline itself and within adjacent areas to establish the disease burden in this locality and limit further northerly squirrelpox spread.LA Wilson, veterinary pathology lecturer, M Marr, postdoctoral research fellow, C Logie, postmortem room technician, K Beckmann, conservation medicine lecturer, PWW Lurz, squirrel ecologist, R Ogden, director of conservation science, E Milne, professor emerita of veterinary clinical pathology Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG email: [email protected] DJ Everest, pathology scientist APHA Weybridge, Addlestone, Surrey KT15 3NBReferences1 Tompkins DM, White AR, Boots M. Ecological replacement of native red squirrels by invasive greys driven by disease. Ecol Lett2003;6:189–962 Sainsbury AW, Nettleton P, Gilray J, et al. Grey squirrels have high seroprevalence to a parapoxvirus associated with deaths in red squirrels. Anim Conserv2000;3:229–33 3 Mclnnes CJ, Coulter L, Dagleish MP, et al. First cases of squirrelpox in red squirrels (Sciurus vulgaris) in Scotland. Vet Rec2009;164:528–314 LaRose JP, Meredith AL, Everest DJ, et al. Epidemiological and postmortem findings in 262 red squirrels (Sciurus vulgaris) in Scotland, 2005 to 2009. Vet Rec2010;167:297–3025 Everest DJ, Tolhurst-Cherriman DAR, Davies H, et al. Assessing a potential non-invasive method for viral diagnostic purposes in European squirrels. Hystrix 2019;30:44–506 White A, Lurz PWW. A modelling assessment of control strategies to prevent/reduce squirrelpox spread. 2014. Scottish Natural Heritage Commissioned Report No 627. https://bit.ly/441TOgM (accessed 8 April 2024)PROFESSIONHistory of the veterinary professionI WRITE in response to the debate article by Bruce Vivash Jones (VR, 16/23 March 2024, vol 194, p 236). As a PhD researcher on the history of the RCVS and veterinary regulation, and a veterinary nurse, I would like to raise some issues with Vivash Jones’ historical evidence. He states that changes to the council structure would create an oligarchy. From his interpretation of an oligarchy I can assure him and our profession that the first RCVS council did work as This finding represents the first identification of squirrelpox north of the central belt20/27 April 2024 | VET RECORD312Fig 2: Squirrelpox virus virions detected in the affected tissue. Bar = 200 nmFig 1: Macroscopic lesions of ulcerative and exudative dermatitis surrounding the eye in a red squirrel (Sciurus vulgaris)Letters 20 April.indd 312Letters 20 April.indd 31216/04/2024 12:4816/04/2024 12:4
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